JP2003278544A - Ventilation structure of water cooling system for vehicles - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A water-cooled EGR cooler can be mounted above a cylinder head without being restricted by the height position of a water injection port for pouring cooling water, and gas-water separation of cooling water The present invention provides an air bleeding structure for a water cooling system for a vehicle, which can favorably perform the above-described steps, and can improve the mountability on a vehicle by downsizing the engine. SOLUTION: On a head cover 20 of an engine 1,
A water inlet 22 for the cooling water 14 is provided at a position higher than the highest level x of the water cooling region of the EGR cooler 13 and the water inlet 2
There is provided a tank 23 having an air collecting function so that the cooling water 14 poured into the tank 2 can be guided to the thermostat 16 through the connecting pipe 24.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air vent structure for a vehicle water cooling system. 2. Description of the Related Art Conventionally, in an engine of a vehicle such as a truck, a part of exhaust gas is extracted from an exhaust side and returned to an intake side, and the exhaust gas returned to the intake side causes a fuel in the engine to be removed. Exhaust gas recirculation (EGR), in which the generation of NOx (nitrogen oxide) is reduced by suppressing the combustion of fuel and lowering the combustion temperature.
circulation) is taking place. Generally, when performing this kind of exhaust gas recirculation, an appropriate position of an exhaust passage extending from an exhaust manifold to an exhaust pipe and an appropriate position of an intake passage extending from an intake pipe to an intake manifold are provided. It is connected by an EGR pipe, and the exhaust gas is recirculated through the EGR pipe. The exhaust gas to be recirculated to the engine is E
When the cooling is performed in the middle of the GR pipe, the temperature of the exhaust gas decreases and the volume of the exhaust gas decreases, so that the combustion temperature is reduced without significantly lowering the output of the engine, and the N gas is effectively reduced.
In some cases, a water-cooled EGR cooler is provided in the middle of an EGR pipe for recirculating exhaust gas to the engine because the generation of Ox can be reduced. FIG. 5 shows an example of an engine equipped with the EGR cooler. In FIG. 5, reference numeral 1 denotes an engine which is a diesel engine, and the engine 1 has a turbocharger 2. Air cleaner 3
Is introduced into the compressor 2a of the turbocharger 2 through an intake pipe 5, and the compressor 2a
The intake air 4 pressurized in the above is sent to an intercooler 6 for cooling, and the intake air 4 is further guided from the intercooler 6 to an intake manifold 7 to be distributed to each cylinder of the engine 1. The exhaust gas 8 discharged from each cylinder is sent to a turbine 2b of the turbocharger 2 through an exhaust manifold 9, and the exhaust gas 8 driving the turbine 2b is discharged to the outside of the vehicle via an exhaust pipe 10. The turbine 2 of the turbocharger 2
The exhaust pipe 10 (exhaust manifold 9 in the example of FIG. 5) upstream of b and the intake pipe 5 downstream of the compressor 2a of the turbocharger 2 are connected by an EGR pipe 11, and the exhaust manifold 9 A part of the exhaust gas 8 can be extracted and led to the intake pipe 5. Here, the EGR pipe 11 has an EGR valve 12 for appropriately adjusting the amount of recirculated exhaust gas 8 and an EGR valve 12 for cooling the recirculated exhaust gas 8.
R cooler 13 and the EGR cooler 13
In this configuration, the temperature of the exhaust gas 8 can be reduced by exchanging heat between the cooling water 14 and the exhaust gas 8. Further, in the engine 1 as described above, a part of the relatively high-pressure cooling water 14 that has just been introduced into the engine 1 is extracted from the engine 1 side and used for cooling in the EGR cooler 13. The cooling water 14 that has been heated by exchanging heat with the exhaust gas 8 by the EGR cooler 13 is joined to the cooling water 14 that has been heated via the engine 1 at a thermostat 16 and guided to a radiator 15. The circulation of the cooling water 14 is performed by a coolant pump 17 driven by the engine 1. When the temperature of the cooling water 14 is low immediately after the start of the engine 1, for example, the thermostat is used. The operation of operation 16 closes the return passage from the radiator 15 and opens the passage for guiding the cooling water 14 from the engine 1 to the coolant pump 17 so that the cooling water 14 is supplied to the radiator 15.
The coolant is directly sent to the coolant pump 17 without passing through the engine 1 to avoid overcooling of the engine 1. [0010] However, in the vehicle as described above, first, the cooling water 14 is first filled to fill all the water cooling systems including the engine 1 and the radiator 15.
There is a problem that the arrangement of the EGR cooler 13 is significantly restricted by the height position of the water injection port for pouring water. That is, as shown in FIG. 6, especially in a vehicle such as a medium-sized truck, the cylinder head 18 of the engine 1 is generally located at the uppermost position of all the water cooling systems. The water inlet 19 is provided in the thermostat 16 or the like so as to open at a position higher than the cylinder head 18. However, since the opening level of the water inlet 19 determines the liquid level of all the water cooling systems, The EGR cooler 13 must be arranged at a position lower than the opening level of the water inlet 19,
Assume that EG is located at a position lower than the opening level of the water inlet 19.
If the R cooler 13 is not disposed, it is difficult to completely bleed the air in the water cooling region in the EGR cooler 13,
When a locally overheated portion (a heat exchange failure portion between the exhaust gas 8 and the cooling water 14) occurs due to an air pool remaining in the water cooling region of the cooler 13, there is a possibility that damage due to stress concentration may occur. An EGR equipped with an EGR cooler 13
The pipe 11 must be disposed in the vehicle width direction from the exhaust system on one side of the engine 1 to the intake system on the other side,
When the EGR cooler 13 is to be accommodated within the height of the engine 1, the EGR pipe 11 must be turned around the front or rear of the engine 1 to pass in the vehicle width direction. A thermostat 16 and a coolant pump 17 are arranged below the cylinder head 18.
Since the transmission and the like are disposed below the EGR cooler 13, the EGR cooler 13 is located at a position lower than the opening level of the water inlet 19 with respect to the current structure of a vehicle such as a medium-sized truck.
It is extremely difficult to arrange the items. In FIG. 6, reference numeral 20 denotes a head cover attached to an upper portion of the cylinder head 18, and reference numeral 21 denotes a cylinder block. In view of such circumstances, the present invention allows a water-cooled EGR cooler to be mounted above a cylinder head without being restricted by the height of a water inlet for pouring cooling water. It is an object of the present invention to provide an air vent structure for a water cooling system for a vehicle, which can satisfactorily separate the air and water, and can make the engine compact and improve the mountability on a vehicle. [0014] The present invention provides a water-cooled EG.
An air vent structure for a vehicle water cooling system provided with an R cooler, wherein a cooling water inlet is provided at a position higher than the highest level of a water cooling region of the EGR cooler, and the cooling water poured into the water inlet is provided by a water cooling system. The present invention relates to an air vent structure for a water cooling system for a vehicle, comprising a tank having an air reservoir function that can be guided to an appropriate location in the vehicle. According to the above means, the following effects can be obtained. [0016] Even if a water-cooled EGR cooler is arranged at a position higher than the cylinder head, the opening level of the cooling water injection port in the tank is higher than the highest level of the water cooling area of the EGR cooler. Since it has the air accumulation function, complete air bleeding in the water cooling region in the EGR cooler is easily realized, and the EGR cooler 1
No air pools remain in the water-cooling area of No. 3, no local overheating due to poor heat exchange between the exhaust gas 8 and the cooling water 14 does not occur, and there is no fear of damage due to stress concentration, and the engine is made compact. It is possible to do. Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show an example of an embodiment of the present invention. In the drawings, portions denoted by the same reference numerals as in FIGS. 5 and 6 represent the same components. In the illustrated example, the structure in which the water inlet 19 is provided above the thermostat 16 as shown in FIG. 6 is eliminated, and a space is created above the thermostat 16, and a water-cooled EGR cooler 13 is provided in this space. It is arranged. The EGR cooler 13 is located at a position higher than the cylinder head 18 of the engine 1.
A water inlet 22 for the cooling water 14 is provided at a position higher than the highest level x of the water cooling area of the GR cooler 13 and the water inlet 22
A tank 23 having an air reservoir function is provided so that the cooling water 14 poured into the thermostat 16 can be guided to the thermostat 16 through the communication pipe 24, whereby the opening level of the water inlet 22 is set at the highest level of the water cooling area of the EGR cooler 13. Level x
I try to be higher. Here, the EGR cooler 13 shown in FIG.
The EGR cooler 13 of this type will be described. In this type of EGR cooler 13, the plate 26 is closed at both axial ends of a cylindrical shell 25 so as to close the end face of the shell 25.
26 are fixedly attached to each of the plates 26, 26.
Both ends of the multiple tubes 27 are fixed in a penetrating state, and these multiple tubes 27 extend inside the shell 25 in the axial direction. In the vicinity of one end of the shell 25, a cooling water introduction pipe 28 for guiding the cooling water 14 from the engine 1 side is connected, and near the other end of the shell 25, A cooling water discharge pipe 29 (see FIGS. 1 and 2) for discharging the cooling water 14 inside the shell 25 to a position higher than the uppermost level x of the water cooling area of the EGR cooler 13 in the tank 23 is connected. 14 is supplied from the cooling water introduction pipe 28 to the inside of the shell 25,
7, and is discharged from the cooling water discharge pipe 29 to the outside of the shell 25. That is, since the area filled with the cooling water 14 inside the shell 25 is the water cooling area of the EGR cooler 13 described above, for example, if the EGR cooler 13 is arranged substantially horizontally, The upper end position of the internal space is the highest level x of the water cooling area. Further, the anti-shell 2 of each plate 26, 26
On the 5th side, a bonnet 3 having an internal space formed in a bowl shape
The bonnet 30 is provided with an exhaust gas inlet 31 at the center and the exhaust gas outlet 32 is provided at the center of the other bonnet 30. The exhaust gas 8 discharged from the engine 1 enters the inside of one of the bonnets 30 from the exhaust gas inlet 31, and heats the cooling water 14 flowing outside the tubes 27 while passing through the inside of the tubes 27. After being cooled by replacement, the other bonnet 30
And is recirculated to the engine 1 from the exhaust gas outlet 32. In FIG. 3, reference numeral 33 denotes a bypass outlet pipe provided at a position facing the cooling water introduction pipe 28 in the diametrical direction of the shell 25.
By removing a part of the cooling water, stagnation of the cooling water 14 is prevented from occurring at a position facing the cooling water introduction pipe 28. On the other hand, the height relationship of each component of the water cooling system configured as described above is schematically shown in FIG. 4, and the tank 23 includes the radiator 15, the thermostat 16, the coolant in the water cooling system. Pump 17,
Oil cooler 34, turbine 2 of turbocharger 2
b, a cylinder tank 21, a cylinder head 18, and an EGR cooler 13. A reservoir tank for absorbing a volume expansion caused by a rise in the temperature of the cooling water 14 is provided in a water inlet 22 of the cooling water 14 in the tank 23. 3
5 is connected, and the cooling water 14 whose temperature has risen by cooling the engine 1 is introduced into the heater core 36 and is used as a heat source of the heater. Although the circulation pipe 37 for the cooling water 14 cooled by the radiator 15 is shown in FIG. 4 so as to be located above the thermostat 16, it is actually arranged at the same height as the thermostat 16. is there. Next, the operation of the above illustrated example will be described. Even if the water-cooled EGR cooler 13 is arranged at a position higher than the cylinder head 18, the opening level of the water inlet 22 for the cooling water 14 in the tank 23 is higher than the highest level x of the water cooling area of the EGR cooler 13. In addition, since the tank 23 has an air collecting function, when the cooling water 14 is first poured from the water inlet 22 to fill all the water cooling systems, the water level in the water cooling area in the EGR cooler 13 is reduced. As the air rises, the upper air in the EGR cooler 13 is easily discharged from the cooling water discharge pipe 29 to the tank 23.
Side, and when the EGR cooler 13 is full of water,
Complete air bleeding without any remaining air pockets is naturally realized. As a result, complete bleeding of the air in the water cooling area in the EGR cooler 13 is easily realized, and no air pool remains in the water cooling area of the EGR cooler 13, and heat exchange between the exhaust gas 8 and the cooling water 14 is performed. No local overheated portion is generated due to the failure, and there is no fear of damage due to stress concentration, and the engine 1 can be made compact. In this manner, the water-cooled EGR cooler 13 can be mounted above the cylinder head 18 without being restricted by the height of the water inlet 22 for pouring the cooling water 14. Separation can be performed favorably, and the engine 1 can be made compact to improve the mountability on a vehicle. The air bleeding structure of the vehicle water cooling system according to the present invention is not limited to the illustrated example described above, and various modifications can be made without departing from the scope of the present invention. is there. As described above, according to the air bleeding structure of the vehicle water cooling system of the present invention, the water-cooling system can be used without being restricted by the height of the water inlet for pouring the cooling water. The EGR cooler can be mounted above the cylinder head, and the water / water separation of the cooling water can be satisfactorily carried out.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main part side view of an example of an embodiment of the present invention. FIG. 2 is a view taken in the direction of arrows II-II in FIG. FIG. 3 is a sectional view showing details of an internal structure of the EGR cooler in FIGS. 1 and 2; FIG. 4 is an overall schematic diagram showing a height relationship between components of a water cooling system in an example of an embodiment of the present invention. FIG. 5 is a schematic plan view showing an example of a supply / exhaust system and a water cooling system of a vehicle equipped with an EGR cooler. FIG. 6 is a side view showing an example of installation of a water inlet in a vehicle. [Description of Signs] 1 Engine 8 Exhaust gas 11 EGR pipe 12 EGR valve 13 EGR cooler 14 Cooling water 15 Radiator 16 Thermostat 17 Coolant pump 18 Cylinder head 20 Head cover 21 Cylinder block 22 Water inlet 23 Tank 24 Communication pipe 29 Cooling water discharge pipe x top level

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Toshiaki Yamazaki             3-1-1 Hinodai, Hino-shi, Tokyo 1 Hino             Automobile Co., Ltd. F term (reference) 3G062 AA01 AA05 ED08

Claims (1)

Claims 1. An air vent structure for a vehicle water cooling system provided with a water-cooled EGR cooler, wherein a cooling water inlet is provided at a position higher than the highest level of a water cooling area of the EGR cooler. An air vent structure for a water cooling system for a vehicle, comprising: a tank having an air reservoir function capable of guiding cooling water poured into the water inlet to an appropriate place in the water cooling system.